Abstract: In the present paper, the non-equilibrium grain-boundary segregation of P atom was
studied in low alloy steels subjected to a low tensile stress at different temperatures. The AES
(Auger electron spectroscopy) experiments and dynamic analyses were conducted to study on the
non-equilibrium grain-boundary segregation of P atom. The research results show that
non-equilibrium segregation of phosphorus occurred at the grain boundaries of the steels
2.25Cr1Mo and 12Cr1MoV, while the critical time reached about 0-1 hour at constant temperatures
773 and 813K. The relationship between the diffusion rate and the diffusion time for the complex
and the phosphorus atom was investigated based on the experimental results. Eventually the
diffusion coefficients of complex and P were calculated with using a proposed dynamic model.

Abstract: Surface alloying is a new method of surface treatment by which an element is diffused
into the surface of another element causing the formation of a solid solution on its surface. Using
this method, the problems of casting methods have been eliminated. In this method, the sample is
sunk into an aqueous solution and is connected to the cathode. Applying enough voltage, lithium
separated from lithium sulphat-sulfuric acid solution diffuses into the aluminum surface. The depth
of diffusion into the aluminum is measured to be 50 to 500μm according to the diffusion time which
is selected to be 1 to 24 hours. Experiments showed that the formed layer is very uniform. It was
also concluded from the experiments that hardness is increased extensively, with the maximum
value of 98HV, and fatigue life is increased by the factor 4. It was also shown that the toughness,
yield stress and ultimate tensile strength of samples are the same as those of pure aluminum.

Abstract: One possibility to run a zero CO2-emission power plant is the oxyfuel combustion process. An efficient technology to separate oxygen from air are processes with oxygen transport membranes. It is important that these membranes have a high permeability additional to high chemical stability under power plant conditions. La0.58Sr0.4Co0.2Fe0.8O3- (LSCF) is a mixed ionic electronic conducting material (MIEC) which is considered to have good permeation properties and a high stability. In this work LSCF based membranes are investigated. Data from a TGA (Thermo-Gravimetric Analyser) have been used to determine the diffusion coefficient of oxygen vacancies in LSCF perovskite type oxides for different temperatures.

Abstract: The effect of compaction of bentonite on the diffusion behavior of uranium was studied for the safety assessment of radioactive waste (storage and disposal practices). Since the permeability of the compacted clay is very low, the main mechanism for radionuclide transport is governed by the diffusion phenomenon. The diffusion process of uranium in compacted clay as a porous medium has been modeled by Fick's second law taking into account the effect of sorption and considering the non-steady state. The diffusion coefficients and profiles concentration values were calculated by a computational method using a numerical program based on the Newton-Raphson algorithm. In this simulation, the experimental values were used to determine the uranium concentration profiles versus depth of the clay pellet. It was concluded that the dry density of the compacted clay and the aqueous solution properties (pH and ionic strength of background electrolyte) played an important role in the uranium transport through compacted clays.